FIELD OF THE INVENTION

The present invention relates to the technical sector concerning metal crown caps. In detail, the present invention relates to a machine for applying paint to metal crown caps by electrophoresis.

DESCRIPTION OF THE PRIOR ART

By metal crown caps are meant those metal closing elements that are applied to a mouth of a recipient (for example a bottle), each comprising a circular wall and a cogged peripheral edge which originates from a circular wall and which projects transversally thereto along all the relative development.

Metal crown caps are obtained by using punches to blank pre-painted metal sheets. Therefore metal crown caps are lacking in paint at least at the relative peripheral edge (i.e. the cogged edge).

Further, during the transport and/or the storage of the metal crown caps, the paint covering them can be damaged and partially removed from the cap. Therefore, the exposed parts of sheet metal, i.e. the parts lacking paint, are subject over time to oxidation, which gives rise to rust and constitutes a potential risk for the final consumer.

SUMMARY OF THE INVENTION

The aim of the present invention is to obviate the above-described drawback. The aim is attained with a solution according to the contents of independent claim 1 .

The solution proposed by the present invention advantageously enables replacing the paint missing on the metal crown caps in a practical, rapid and particularly efficient way.

In this way the parts of the cap lacking in paint (for example the peripheral edge) oxidise and give rise to rust, thus becoming potentially dangerous for the final consumer (as occurred in the prior art).

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantageous characteristics of the invention will be more precisely specified in the following description, with the aid of the appended tables of drawings, in which:

- figure 1 illustrates a front view of a machine for application of paint by electrophoresis on metal crown caps according to the present invention, in which some parts have been highlighted in order to better understand the functioning thereof;

- figure 2 is a partly-sectioned view from above of figure 1 ;

- figure 3 is a larger-scale detail of a machine according to the present invention and of a metal crown cap, according to a preferred embodiment.

DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to the accompanying figures of the drawings, (1) denotes a machine for application of paint (V) by electrophoresis on metal crown caps (2) according to the present invention.

The electrophoresis process, in general, consists in the single-directional movement of electrically-charged particles, suspended or dissolved in a conductor liquid medium (in this case paint), by action of an electrical field. By metal crown caps (2) are meant those metal closing elements that are applied to the mouth of a recipient (for example a bottle) each comprising a circular wall (20) and a cogged peripheral edge (21) which originates from the circular wall (20) so as to project transversally with respect thereto (along a whole extension thereof).

In general, the metal crown caps (2) are obtained by blanking with punches of pre-painted metal sheets. Therefore, the crown metal caps (2) are free of paint at least at the relative peripheral edge (21) (i.e. the cogged edge). Further, the metal crown caps (2) can be accidentally lose the paint even during transport and/or storage thereof.

The machine (1) for application of paint (V) on metal crown caps (2) by means of electrophoresis of the present invention comprises an inlet conveyor (3) for providing metal crown caps (2) in a vertical orientation. In other words, the metal crown caps (2) are made available by the inlet conveyor (3) so that the relative circular wall (20) is vertical (see the detail of figure 1).

The machine (1) further comprises a tub (4) containing paint (V) for at least partly immersingly receiving the metal crown caps (2). In particular, the paint (V) is suitable for use in carrying out a painting operation by means of electrophoresis, i.e. the paint (V) is electrically chargeable.

The machine (1) further comprises an outlet conveyor (5) for receiving the metal crown caps (2) which have been painted in the tub (4) by means of electrophoresis and which are vertically orientated. In other words, the metal crown caps (2) are received by the outlet conveyor (5) with the relative circular wall (20) arranged vertically (reference is made in particular once more to figure 1).

The machine (1) further comprises a conveyor unit (6) for taking the metal crown caps (2) from the inlet conveyor (3) so as to transport the metal crown caps (2) along a transport pathway which includes at least partial immersion of the metal crown caps (2) in the tub (4), and to make the metal crown caps (2) available to the outlet conveyor (5) (orientated vertically).

In detail, the conveyor unit (6) comprises: a conveyor member (7) which is interposed between the inlet conveyor (3) and the outlet conveyor (5), which conveyor member (7) is arranged above the tub (4), which is rotating about a horizontal axis and which comprises an annular conveyor surface (70) for contacting the circular wall (20) of the metal crown caps (2) during the transport of the metal crown caps (2) along the transport pathway.

The conveyor unit (6) further comprises gripping and retaining means (8) for taking the metal crown caps (2) from the inlet conveyor (3) and anchoring them to the annular surface (70) and for retaining the metal crown caps (2) against the annular surface (70) during the transport of the metal crown caps (2) along the conveyor pathway.

The machine (1) of the invention further comprises a conductor element (9) which is electrically conductible and which is arranged so as to contact the peripheral edge (21) of the metal crown caps (2) during the at least partial immersion of the metal crown caps (2) in the tub (4).

In particular, in order to enable the electrophoresis process, the conductor element (9) is electrically charged (for example with a positive charge) by electrical supply means (not illustrated). Since the conductor element (9) contacts the peripheral edge (21) (free of paint) of the metal crown caps (2), the electrical charge is transferred to each metal crown cap (2).

In the same way, the paint (V) (which is of a type suitable for the electrophoresis process) is electrically charged with an opposite electrical charge to the charge the conductor element (9) is charged (for example a negative charge).

Therefore, when the metal crown caps (2) are immersed in the paint (V), internally of the tub (4), during the rotation of the rotating member (7), the particles of paint (V) are attracted by the opposite electrical charge of the metal crown caps (2) and go to deposit on the metal crown caps (2) at the exposed parts of the metal sheet.

For example, the paint (V) can be electrically charged via the tub (4), which can comprise at least a portion made of a conductor material or can be made of a conductor material.

The machine (1) for application of paint (V) by means of electrophoresis on metal crown caps (2) of the present invention is structurally simple and particularly functional.

The fact that the metal crown caps (2) are contacted by the annular surface (70) at the relative circular wall (20), i.e. are vertically arranged during transport and in this orientation are retained by the gripping and retaining means (8), guarantees stability thereof during the conveyor pathway, even at high speeds.

In an embodiment of the invention, the gripping and retaining means (8) are magnetic and solidly constrained to the conveyor member (7). For example, the gripping and retaining means (8) can be constituted by a plurality of magnets solidly constrained to the conveyor member (7) at the annular surface (70).

In a further embodiment, the gripping and retaining means (8) can comprise a magnetic wall which defines the annular surface (70). In other words, the annular surface (70) can be formed by a magnetic surface.

This embodiment advantageously guarantees the effective anchoring of the metal crown caps (2) to the annular surface and is also simple to realize.

It must be taken into account that the rotation velocity of the conveyor member (7) is particularly high, and that therefore the anchoring of the metal crown caps (2) to the annular surface (70) must be optimal.

The gripping and retaining means can alternatively comprise aspirating means.

In a preferred embodiment of the invention, the annular surface (70) is circular and the conveyor member is a rotating disc (7) which conforms the annular surface (70) at the relative circular edge (71). This embodiment is particularly functional.

In a preferred embodiment, the conductor element is a conductor disc (9) (see figure 1) which is concentric with the conveyor member (7), which conductor disc (9) has a smaller diameter than the conveyor member (7) so as to function as an abutment for the metal crown caps (2) taken from the inlet conveyor (3) during the conveying of the metal crown caps (2) along the conveyor pathway. In other terms, the metal crown caps (2) collected by the inlet conveyor (3) (with a vertical orientation) by the gripping and retaining means (8) of the conveyor unit (6) are contacted at the relative circular wall (20) by the annular surface (70) of the conveyor member (7), and at the relative peripheral edge (21) by the conductor disc (9).

In other terms, the conductor disc (9) functions as a guide for the metal crown caps (2) during the transport thereof along the conveyor pathway. In detail, the conductor disc (9) can contact the peripheral edge (21) of the metal crown caps (2) by means of the relative circular edge.

In the preferred embodiment of the invention, the conductor disc (9) exhibits a cogged circular edge (90) conformed so as to mesh with the cogged peripheral edge (20) of a metal crown cap (2). Further, in this variant the conveyor member (7) is rotating with respect to the conductor disc (9) at a velocity that is such as to enable rotation of a metal crown cap (2) (anchored to the annular surface (70)) on itself during the rotation of the conveyor member (7 (see the detail of figure 3).

In other words, the difference in rotation velocity between the conveyor member (7) and the conductor disc (9) is such as to rotate a metal crown cap (2) about itself during the rotation of the conveyor member (7).

The machine (1) can further comprise a frame (10) with respect to which the conveyor member (7) rotates, and with respect to which the conductor disc (9) is solidly constrained during the rotation of the conveyor member (7). In other terms, with reference to the embodiment described herein above, the conductor disc (9) can be stationary during the rotation of the conveyor member 87), i.e. it can have a nil rotation velocity, i.e. equal to zero.

The conductor disc (9) can for example exhibit a rotation velocity of less than the rotation velocity of the conveyor member (7), as long as the rotation velocity of the conveyor member (7) with respect to that of the conductor disc (9) (i.e. the difference between the two rotation velocities) is such as to enable rotation of a metal crown cap (2) about itself during the rotation of the conveyor member (7).

The fact that the metal crown caps (2) rotate on themselves enables their immersion, even partially, in the paint (V) of the tub (4), in any case guaranteeing the possibility of realising the painting thereof (completely) by electrophoresis (this variant is illustrated in the figures). In fact, each metal crown cap (2), as it rotates on itself internally of the tub (4), in any case enables completing the painting thereon.

This embodiment advantageously guarantees a greater cleanliness of the whole work environment and an excellent painting of the metal crown caps (2). As illustrated in figure 1 , the rotating member (7) in this variant is not even partially immersed in the tub (4) during the rotation, i.e. it does not enter into contact with the paint (V), and therefore does not generate splashing of paint (V) into the surrounding work environment.

In the preferred embodiment illustrated in the accompanying figures, the inlet conveyor (3) is a loop conveyor comprising: two pulleys (31 , 32) activatable in rotation with respect to corresponding vertical axes; an active branch (33) drawn in rotation by the pulleys (31 , 32); magnetic means (34) arranged at the active branch (33) so as to retain the metal crown caps (2) with a vertical orientation (see in particular figure 2).

The active branch (33) of the inlet conveyor (3) can be arranged flanked and adjacent to the annular surface (70) of the conveyor member (7).

For example, the active branch (33) can be magnetic.

This configuration of the inlet conveyor (3) advantageously guarantees retaining the metal crown caps (2) even when they are moved at a high speed. Once more according to the illustrated embodiment, the outlet conveyor (5) is a loop conveyor comprising: two pulleys (51 , 52) activatable in rotation with respect to corresponding vertical axes; an active branch (53) drawn in rotation by the pulleys (51 , 52); magnetic means (54), arranged at the active branch (53) so as to retain the metal crown caps (2) with a vertical orientation (see in particular figure 2).

The active branch (53) of the outlet conveyor (5) can be arranged flanked and adjacent to the annular surface (70) of the conveyor member (7).

For example, the active branch (53) can be magnetic.

In this case too, the retaining of the metal crown caps (2) is optimally guaranteed.

In the preferred embodiment, which includes the gripping and retaining means (8) of the rotating unit (6) being magnetic and also includes the inlet conveyor (3) and the outlet conveyor (5) each comprising magnetic means (34, 54), the machine (1) is configured so that the magnetic force exerted on the metal crown caps (2) by the gripping and retaining means (8) is greater than the magnetic force exerted on the metal crown caps (2) by the magnetic means (34) of the inlet conveyor (3). Further, the magnetic force exerted on the metal crown caps (2) by the magnetic means (54) of the outlet conveyor (5) will have to be greater than the magnetic force exerted on the metal crown caps (2) by the gripping and retaining means (8). In other words, the magnetic force of the gripping and retaining means (8) will have to overcome the magnetic force of the magnetic means (34) of the inlet conveyor (3), and the magnetic force of the magnetic means (54) of the outlet conveyor (5) will have to overcome the magnetic force of the gripping and retaining means (8) so as to enable transfer of the metal crown caps (2) from the inlet conveyor (3) to the conveyor unit (6) and therefore to the outlet conveyor (5).

It is understood that the above has been described by way of non-limiting example, and any eventual constructional variants are understood to fall within the protective scope of the present technical solution, as claimed in the following.